CEN20LA413

The pilot was taxiing the weight-shift control aircraft to the runway to depart when his wife heard a loud “bang” from inside the house. There were no witnesses to the accident. The aircraft was found upright against a fence along a grass taxiway. The aircraft sustained substantial damage to the fuselage. The pilot’s son reported that his father recently replaced the throttle cable on the aircraft. After the throttle cable change, the pilot reported the throttle cable was “sticking.” The engine was examined, and the throttle cable was found installed correctly at the engine and at the cockpit. The throttle cable at the cockpit throttle control position did not have a full range of motion and was found jammed with little to no movement available; however, whether this occurred before the accident or was the result of impact damage could not be determined. Available medical information provided no evidence that a medical factor contributed to the accident. The circumstances of the accident are consistent with a loss of control while the pilot was taxiing the aircraft; however, the reason for the loss of control could not be determined based on the available evidence.

The FAA has published the Weight-Shift Control Aircraft Flying Handbook (FAA-H-8083-5). This document discusses emergency procedures such as a stuck or runaway throttle and states in part: Throttles can stick above idle or unexpectedly increase, which is called a runaway throttle. If on the ground, a runaway throttle can be disastrous if not anticipated and mitigated. A pilot (and instructor, if teaching) should always have access to the ignition system in order to shut it off immediately in the event of a throttle stuck above idle or a runaway throttle. The pilot’s wife reported that he had owned the aircraft less than 3 months at the time of the accident. The airframe, engine, and propeller maintenance records were not available for review. The elevation of the private grass airstrip and accident site was about 1,130 ft above msl. On September 19, 2020, about 1845 central daylight time, an experimental, amateur-built Cosmos Phase III weight-shift control aircraft, N7024L, was substantially damaged when it was involved in an accident near Wayne, Oklahoma. The private pilot sustained fatal injuries. The aircraft was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The pilot was taxiing the aircraft on his property for a short flight. The pilot’s wife did not observe the accident sequence but reported hearing a loud “bang” while she was inside their home. The aircraft was found upright against a fence next to a horse stable along a grass taxiway that the pilot would use to access the private grass runway. The aircraft sustained substantial damage to the fuselage. The pilot’s son reported that his father recently replaced the throttle cable on the aircraft. After the throttle cable change, the pilot reported the throttle cable was “sticking.” Whether the pilot performed any ground runs to check the operation of the throttle cable on the day of the accident was not determined. According to postaccident medical records, the pilot experienced cardiac arrest at the scene of the accident. Emergency medical services performed cardiopulmonary resuscitation for about 20 minutes. The pilot was transported by air ambulance to the hospital emergency department. He was admitted to the trauma intensive care unit, on sedation and blood pressure support medication, with a breathing tube. He underwent extensive imaging that revealed multiple serious injuries, including a brain injury; however, no significant pre-accident natural disease was noted. Laboratory testing was consistent with his critical illness; no toxicology testing was documented. The postaccident medical records contained some medical information provided by the pilot’s wife while the pilot was in the hospital. According to this information, the pilot had a history of high blood pressure and replacements of both knees and used hydrocortisone orally twice daily. Hydrocortisone is a prescription medication that is not generally considered impairing. It can be used totreat a variety of inflammatory conditions or to supplement low adrenal gland hormone; the reason the pilot used it was not specified. According to the postaccident medical records, the pilot’s wife reported that the pilot had been independent and active before the crash and did not use alcohol or recreational drugs. The pilot died on September 26, 2020, after progression of his brain injury. The Office of the Chief Medical Examiner, Oklahoma City, Oklahoma, produced a death investigation report. No autopsy was performed. According to the death investigation report, the cause of death was acute multiple blunt force trauma sequela, and the manner of death was accident. In a telephone interview with the NTSB, the pilot’s wife stated that the pilot had appeared fine and healthy on the day of the accident. She stated that he had not had any medical conditions, other than taking an unspecified medication for high blood pressure. Medications typically used as first-choice treatments for high blood pressure generally are not impairing. The calculated estimated density altitude for the accident site was 2,404 ft above mean sea level (msl). The pilot’s flight records were not available for review. The aircraft was found about 500 ft from the airstrip. The right wing strut came to rest on top of a large bale of hay. Federal Aviation Administration (FAA) aviation safety inspectors documented the accident site and examined the airframe and engine. All major structural components and flight control surfaces were located at the accident site. Flight control and engine control continuity were established. The damage sustained to the three-blade propeller was consistent with the propeller turning under engine power when it impacted terrain. The fuel tank was intact and was full of fuel. The ignition system key was found at the ON position. The engine was examined, and the throttle cable was found installed correctly at the engine and at the cockpit. There were no part number identification markings on the throttle cable. The throttle cable at the cockpit throttle control position did not have a full range of motion and was found jammed with little to no movement available; however, whether this occurred prior to the accident or was the result of impact damage could not be determined.